Hyperproliferation of epidermal cells in mammals can be induced virally as well as by body dysfunctions. Herpes simplex and herpes zoster infections are examples of the virally-induced cell growth initiators. Cold sores are further examples of virus-induced cellular proliferation conditions. Psoriasis is a skin disease characterized by an apparent disruption in a number of regulatory functions. Both the length of cell cycle and cell turnover time are considerably shortened in the epidermis of such infected skins. The rapidly growing epidermal cells also fail to differentiate normally. Anti-psoriasis drugs such as methotrexate, anthralin, cytosine arabinoside and daunorubicine have been found to inhibit cell proliferation by inhibiting the thymidine or deoxyuridine incorporated into DNA so as to prevent protein growth.
It is known from Experientia 29, 1442-43, 1559-1561 (1973) and 30, 1272 (1974) that 2-amino-4,6-dichloropyrimidine is effective to inhibit the growth of polio virus in vitro by interfering with the intercellular assembly of the viral particle. It acts as the stage of the capsid precursors, impairing structural protein VPO formation.
The compounds of the present invention are known to have anti-inflammatory activity and to be useful in the protection of the human skin against the harmful effects of radiation.
It has been surprisingly found in accordance with the present invention that certain anti-inflammatory compounds possess the additional ability to act as metabolic inhibitors in the growth of epidermal cells in those conditions caused by viral infections as well as of non-specific origin. The combination of useful properties permits the compounds of the present invention to be applied not only to obtain relief from existing inflammatory conditions of the skin but to further act as an inhibitor of skin rashes caused by cellular proliferation due to the underlying condition.